The man who killed Joe McKnight got out of his car and pointed his weapon at a Navy officer who rushed to the scene to try to help ... cops say.
Sheriff Newell Normand says they interviewed Ronald Gasser for more than 10 hours and spoke with more than 160 witnesses in the case.
They believe after Gasser shot McKnight following a verbal altercation -- he got out of the car to see McKnight's body ... and was approached by a military officer.
The Naval officer told Gasser to put his gun away because it was not in his best interest to shoot a Naval officer.
The Naval officer and cops then tried to help McKnight -- but it was too late.
Sheriff Normand says Gasser has insisted he was fearing for his life -- and that's why he pulled his weapon during the altercation.
However, the sheriff says ... "Suffice it to say that obviously, a lot of the independent witnesses have provided information that doesn't completely square up with Mr. Gasser's statement."